A compound having a polymerizable group (polymerizable compound) is used in various optical materials. For example, a polymerizable composition containing a polymerizable compound, which is in a liquid crystal state, is subjected to alignment, and then subjected to polymerization, thereby making it possible to produce a polymer having a uniform alignment. Such a polymer can be used for polarization plates, retardation plates and the like which are necessary for displays. In many cases, for satisfying necessary optical characteristics, polymerization speed, solubility, melting point, glass transition temperature, polymer transparency, mechanical strength, surface hardness, heat resistance and lightfastness, a polymerizable composition containing two or more kinds of polymerizable compounds is used. In such a case, the polymerizable compound to be used is required to impart good properties to the polymerizable composition without imposing any negative influence on the other characteristics thereof.
For improving the view angle of a liquid crystal display, the wavelength dispersion in terms of birefringence of a retardation film is required to lower or reverse. As a material for that purpose, various polymerizable liquid crystal compounds having reverse wavelength dispersion or low wavelength dispersion have been developed. However, such polymerizable compounds have a problem that, when formed into filmy polymers, they undergo change over time in phase difference and reverse wavelength dispersion, and have a problem that, when formed into filmy polymers and kept irradiated with UV light for a long period of time, peeling from substrates is likely to be caused (PTLs 1, 2 and 3). In the cases where films that are prone to change over time in phase difference and reverse wavelength dispersion or films that are prone to peeling are used, for example, in displays, there may occur a case where the screen color becomes unnatural in long-term use or a case where intended optical characteristics could not be obtained, so that a problem of significantly degrading the quality of display products is caused. Consequently, development of a polymerizable liquid crystal compound that has low wavelength dispersion or reverse wavelength dispersion and can solve these problems has been desired.